The present disclosure relates to control unit capable of being added to, for example, thermostat-humidistat containers (chambers) and improving temperature and humidity distribution efficiency.
For example, an environmental tester such as a thermostat-humidistat container has been used for stability tests of pharmaceuticals, or the like in order to test the performance of a product under predetermined temperature and predetermined humidity. In such an environmental tester, a temperature sensor and a humidity sensor are provided in a thermostat-humidistat container surrounded by adiabatic walls, and an air conditioner including a refrigerator, a humidifier, and a heater is controlled based on values measured by these sensors, thereby allowing circulation of air between the thermostat-humidistat container and the air conditioner so that the temperature and the humidity in the thermostat-humidistat container are kept to target temperature and target humidity, respectively (see, for example, Japanese Unexamined Patent Publication No. H07-140061).
In conventional environmental testers, a temperature sensor and a humidity sensor for measuring the control physical quantities used to control the air conditioner are generally arranged near an outlet (or an inlet) of the conditioned air. This is because the temperature and the humidity measured near the outlet of the conditioned air can change quickly in response to the control of the air conditioner with a small lag, thereby allowing stable control of the air conditioner.